For old players its unclear, for new players its complete chaos:
ATM its impossible to plan ahead towards maps/matches, since there is no clear table explaining for every nation which BR will give you which maps (with exact probabilities, since these are coded somewhere) and which enemies (with corresponding probabilities too).
All these infos need to be written down somewhere so people can know what to get and whether it make sense to play something like Germany BR4 over BR5 to get more American teams (even if they might be BR 5).
The less clear a game is, the less new players will like and invest into it.